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May 13, 2013
05/13

by
Heltai, Jeno, 1871-1957

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39

Sep 23, 2013
09/13

by
Luca Heltai; Francesco Costanzo

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Dirac-delta distributions are often crucial components of the solid-fluid coupling operators in immersed solution methods for fluid-structure interaction (FSI) problems. This is certainly so for methods like the Immersed Boundary Method (IBM) or the Immersed Finite Element Method (IFEM), where Dirac-delta distributions are approximated via smooth functions. By contrast, a truly variational formulation of immersed methods does not require the use of Dirac-delta distributions, either formally or...

Source: http://arxiv.org/abs/1110.2063v2

90
90

Jul 20, 2013
07/13

by
Marino Arroyo; Antonio DeSimone; Luca Heltai

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Fluid membranes made out of lipid bilayers are the fundamental separation structure in eukaryotic cells. Many physiological processes rely on dramatic shape and topological changes (e.g. fusion, fission) of fluid membrane systems. Fluidity is key to the versatility and constant reorganization of lipid bilayers. Here, we study the role of the membrane intrinsic viscosity, arising from the friction of the lipid molecules as they rearrange to accommodate shape changes, in the dynamics of...

Source: http://arxiv.org/abs/1007.4934v1

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46

Sep 18, 2013
09/13

by
Luca Heltai; Saswati Roy; Francesco Costanzo

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We present the implementation of a solution scheme for fluid-structure interaction problems via the finite element software library deal.II. The solution scheme is an immersed finite element method in which two independent discretizations are used for the fluid and immersed deformable body. In this type of formulation the support of the equations of motion of the fluid is extended to cover the union of the solid and fluid domains. The equations of motion over the extended solution domain govern...

Source: http://arxiv.org/abs/1209.2811v1

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32

Jul 20, 2013
07/13

by
Andrea Mola; Luca Heltai; Antonio DeSimone

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We present an innovative numerical discretization of the equations of inviscid potential flow for the simulation of three dimensional unsteady and nonlinear water waves generated by a ship hull advancing in water. The equations of motion are written in a semi-Lagrangian framework, and the resulting integro-differential equations are discretized in space via an adaptive iso-parametric collocation Boundary Element Method, and in time via adaptive implicit Backward Differentiation Formulas (BDF)...

Source: http://arxiv.org/abs/1203.3384v2

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53

Sep 22, 2013
09/13

by
François Alouges; Antonio DeSimone; Luca Heltai

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We propose a computational method to solve optimal swimming problems, based on the boundary integral formulation of the hydrodynamic interaction between swimmer and surrounding fluid and direct constrained minimization of the energy consumed by the swimmer. We apply our method to axisymmetric model examples. We consider a classical model swimmer (the three-sphere swimmer of Golestanian et al.) as well as a novel axisymmetric swimmer inspired by the observation of biological micro-organisms.

Source: http://arxiv.org/abs/0906.4502v3

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Jun 30, 2018
06/18

by
Luca Heltai; Josef Kiendl; Antonio DeSimone; Alessandro Reali

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The interaction between thin structures and incompressible Newtonian fluids is ubiquitous both in nature and in industrial applications. In this paper we present an isogeometric formulation of such problems which exploits a boundary integral formulation of Stokes equations to model the surrounding flow, and a non linear Kirchhoff-Love shell theory to model the elastic behaviour of the structure. We propose three different coupling strategies: a monolithic, fully implicit coupling, a staggered,...

Topics: Physics, Condensed Matter, Numerical Analysis, Fluid Dynamics, Soft Condensed Matter, Mathematics

Source: http://arxiv.org/abs/1702.04502

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68

Jul 20, 2013
07/13

by
François Alouges; Antonio DeSimone; Luca Heltai; Aline Lefebvre; Benoît Merlet

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We study self propelled stokesian robots composed of assemblies of balls, in dimensions 2 and 3, and prove that they are able to control their position and orientation. This is a result of controllability, and its proof relies on applying Chow's theorem in an analytic framework, similarly to what has been done in [3] for an axisymmetric system swimming along the axis of symmetry. However, we simplify drastically the analyticity result given in [3] and apply it to a situation where more complex...

Source: http://arxiv.org/abs/1007.4920v2